Extremely low sound on iPhone 11 Pro Max in Toyota CHR

I just purchased a 2020 Toyota CHR. When I plug my phone into the USB the volume seems to diminish. Then when I switch over to bluetooth the volume starts off pretty loud(which I like) but then no later than a minute, the volume(not the number) goes down to non existent. I like to jam out but when I have my volume on MAX and I can still hear myself talk, then it just ruins my entire trip. Why is this happening? Does anyone else have this problem? Please tell me there is a solution...I beg you.

Also, this happens not only with the Apple Music app but with other apps as well such as Spotify, and Amazon music.